Laser Surface Texturing in Powder Bed Fusion: Numerical Simulation and Experimental Characterization

Laser surface texturing can improve the surface properties of the metallic components. In this work, surface texturing has been carried in a powder bed fusion of Inconel 718 (IN718) rather than material removal process. A 2D finite element method (FEM) has been built to simulate the thermo-fluidic dynamics of surface texturing, incorporating the phase-field method in the preplaced IN718 powder. The temperature and induced velocity fields have been predicted using transient heat transfer and fluid flow based on the conservation of mass, momentum, and energy in the melt pool. Furthermore, the roles of driving forces such as Marangoni force, recoil pressure, and thermal buoyancy force on the melt pool behavior have been evaluated. Micro-textures were developed using laser on the powder bed by using different scanning patterns, such as line, circle, hatch and convex dimple. The effect of process parameters (pitch distance, number of pulses and number of layers) on the surface hydrophobicity were evaluated by measuring the contact angle, where the convex dimple texture exhibited the maximum contact angle. The hydrophobicity was affected by the ripples (2nd level of roughness) on the surface, which increased with an increase in number of pulses.